Substation telephone set



ct. 16, 1934. H. H. IDE 1,976,729

SUBSTATION TELEPHONE SET Filed Feb. 15. 1932 2 sheets sheet l Oct16,1934, HHJDE V 1,976,729

SUBSTATION TELEPHONE SET Filed Feb. 15. 1932 2 Sheets-Sheet 2 Inventor I Harri] I-LIEZG ranted on. is, 1934 1,975,729 SUBSTATION TELEPHONE SET Harry E. Ide, La Grange, ML, error to Associated Electric Laboratories, Inc., Chicago, 1131., a. corporation of Delaware Application February 15, 1932, Serial No. 592,987

. 4 Claims.

This invention relates in general to telephone substation sets, but more particularly to telephone substation sets for use in small intercommunicating systems, and the principal object of the invention is to design a substation telephone that is economical to manufacture, durable in construction, simple to operate, and at the same time retains all of the features common to a regular telephone substation, such as talking, l0 listening, and signalling.

An object of the invention resides in the design of a new and improved circuit arrangement for a substation telephone set in combination with another similar telephone to form a private intercommunicating system.

In accordance with the above object only a single pair of line wires, together with a battery conductor are provided between two permanently connected telephones. Signalling and talking takes place over the battery conductor and one of the line wires when one telephone calls the the other; and when the second telephone calls the first, signalling takes place over the battery conductor and the other line wire while talking proceeds over the first line wire and the battery conductor.

A particular feature of the invention resides i providing a three-position switch operating memher which in one position with the handset resting on the telephone cradle. closes a point in the ringing circuit of that telephone and with the handset removed closes a point in its talking circuit; while with the handset removed, the member may be manually actuated by the user to signal the other telephone station, thereby dispensing with the use of a separate ringing or signalling key.

Other objects and features not specifically pointed out will be apparent hereinafter in the description, which, together with the accompanying two sheets of drawings, illustrates a preferred embodiment of the invention. In the drawings, Fig. 1 illustrates a perspective front view and on a reduced scale of a cradle type of telephone constructed in accordance with the invention; Fig. 2 is a full size top view of the base of the telephone of Fig. 1 illustrating the apparatus mounted thereon; Fig. 3 shows a full size side view of the switch operating member detached from the telephone together with the .contact springs actuated thereby, all in their normal position with the handset resting on the member; Fig. 4 is a similar view with the handset removed from the switch actuating member and the contact springs shown in the talking position; while Fig. 5 illustrates the position of the contact springs and the actuating member when the user is signalling the other telephone; Fig. 6 illustrates an underside view of the handle of the handset with the transmitter and receiver units removed to show the construction of the same; Fig. 7 shows a side view of the receiver unit with the casing in section; Fig. 8 is a side view of the transmitter unit with the casing and the microphone unit shown in section; Fig. 9 is a perspective view of the microphone unit, together with its support; Fig. 10 is a, bottom view of the dummy calling device'of Fig. 1 showing the ratchet mechanism for generating sound waves simulating dialling; and Fig. 11 is a schematic diagram of 7c the circuit connections extending between two telephones.

Referring now specifically to Fig. 1, thebase 5 of the telephone is formed out of a sheet metal stamping. A U-shaped cradle member 6 is riveted to the top of this base and has a pair of ears for supporting the handset 7. A reinforcing member 8 is welded between the two ears of the cradle member 6 and has projections extending through the top of the base 5 for securing it 39 thereto. A switch operating member 9, made of insulating material, extends through the reinforcing member 8 and a hole in the top of the base 5. This member projects upward a sumcient distance so as to be operated by the handset 7 35 when it is in the normal position, as shown in Fig. 1. The handset 7 has a transmitter unit 10 and a receiver unit 11 secured on opposite ends of it by means of pairs of screws 12.

Referring to Fig. 2, the base plate 14 is made of stamped metal of a size sumcient so as to form a perfect fit with the inside of the base member 5. The upturned rim 15 fits inside of the base of the telephone 5 and is properly located by means of. an appropriate notch 17 engaging a similar one in the base 5. The plate 14 is also. provided with projecting portions 16 to slightly raise the major portion thereof off any supporting surface upon which it may be set. A clip 18 is riveted to the plate 14 and serves as a support and strain reliever for the telephone wires ontering the rear of the base 5 through a hole (not shown). A pair of insulating plates 19, one supported on top of the other, are riveted to the base plate 14 and serve as a mounting plate for the wire terminals 20, 21, and'22 to which the condoctors entering the telephone stand are connected'. A sheet of insulating material 23 is riveted to the base plate 14, and supports a metal plate 24 riveted onto it. The metal plate 24 has no a pair of upwardly projecting portions, one of which supports the buzzer coil 25, while from the other the armature 26-and interrupter arrangement are supported. A bracket 30 is riveted to the base plate 14 and serves as a support for a plurality of contact springs 32, 33, 34, 35, and 36 by means of which the necessary circuit switching operations are performed. Each of these contact springs is separated by a suitable insulating plate and the assembly as a whole is clamped to the bracket 30 by means of a pair of screws 31. The bracket 30 supports the set of contactsprings in a position immediately below the switch operating member 9 so that they can be actuated thereby. An insulating bushing 37 is se ured to spring 33 and is adapted under certain conditions to close springs 35 and 36.

Fig. 3 illustrates in side elevation the position of the switching member 9 with the handle of the handset '7 normally resting upon it between the ears of the cradle member 6 of the telephone. In this position the contactsprings 32 and 33 are separated, while contact springs 33 and 34 are made, and as will be further pointed out hereinafter, prepare the circuit'of the buzzer of the telephone for operation. Contact springs 35 and 36 for signalling the other telephone are at this time not closed.

Fig. 4 shows the set of springs in the position in which they are operated when the handset 7 has been removed from the cradle 6 thereby allowing the switching member 9-to move upward to permit the contact springs 32 and 33 to close the circuit of the handset 7 so that talking and listening can take place. and at the same time to open the contact springs 33 and 34 to interrupt the circuit of the buzzer of the telephone. Springs 35 and 36 are not closed in this position of the switch member 9. Fig. 5 shows the position of the switch actuating member 9 when the user of the telephone holds it actuated to signal the person at the other telephone. This is accomplished by the user pressing down the switch operating member 9 until his finger engages the base of the cradle portion 3, which, it will be noted, is a little further than illustrated in Fig. 3 in which the handset '7 rests upon the switching member 9. In the position shown in Fig. 5 the switch member 9 opens the' contact springs 32 and 33, closes contact springs 33 and 34, and by means of the insulating bushing 37 actuates the contact springs 35 and 36 to close the signalling circuit to the buzzer-of the other telephone. Figs. 3. 4. and 5, as pointed out, illustrate the three different positions assumed by the switch operating member 9 during the operation of the telephone.

In Fig. 6 is shown a full size view of the handset. It is constructed of relatively thin sheet metal which is first blanked out and then stamped and the edges bent over towards each other so that the handle portion '7 assumes a circular cross section having the slots 40 and 41 at right-angles to each other where the ends come together. This arrangement does not require any overlapping or riveting of the ends. Shallow cupshaped members 43 and 44 are formed on each end of the handle 7, the receiver unit fitting in the cup-member 44 while the transmitter unit fits in the cup-member 43. 'These units are each secured in the cup-members by means of a pair of screws'l2 extending through holes 45 and contemporary threaded holes in the bottom of the casings of the receiver and transmitter units. An opening 42 in the bottom of the cup member 43 serves as an entrance for the conducting wires of the units. The wires between the receiver .unit in the cup member 44 and the transmitter unit in the cup member 43 extend through the hollow handle 7 of the handset and are inserted by being forced through the slot'40 of the handle 7.

The receiver unit shown in Fig. 7, comprises essentially the stamped metal casing 11 which is cup-shaped, together with the ear piece 50 which is crimped around the flared edges of the cup 11 as indicated at 51. The diaphragm 52 of the receiver is clamped between the crimped edges of the ear piece 50 and the casing 11. This arrangement precludes the possibility of opening up the receiver unit by unskilled persons or children and prevents damage to the internal mechanism. The receiver coil 53 has a threaded extension 54 formed on the end of its core so that the adjusting nut 55 can be threaded onto it. A flat leaf spring 56 normally urges the coil 53 towards the diaphragm 52 and the air gap between the end of the core and the diaphragm is conveniently adjusted by turning the nut 55 on the extension of the core 54 to compress or expand leaf spring 56. A look washer between the nut 55 and the casing 11 and another between the spring 56 and the end of the core 53 securely hold the coil in the desired adjusted position.

The transmitter unit shown in Fig. 8 comprises a stamped metal casing 10, similar to the casing 11 of the receiver. The mouthpiece 60 has a flared edge which is crimped. to the top flared edge of the casing 10. A microphone supporting member has a pair of oppositely disposed legs 62 and 63 ,on each side of the microphone and the top of the casing 10 forms the sole sup- ,port of the microphone unit. The microphone supporting bracket has an enlarged central portion with an opening therein into which the insulating cup-shaped microphone container 64 extends. A short projecting ear 68 extending from either side of the supporting bracket is clamped over the back side of the cup-member 64 and securely holds the microphone unit in position opposite the sound openings in the mouthpiece 60. The microphone unit comprises a button-shaped rear electrode 65 having a stem projecting from the rear of the insulated cup 64 so that a wire can be soldered to it. The front electrode comprises preferably a thin gold plated diaphragm 66 spaced opposite the rear electrode 65 by the 'felt washer 69 and held in position in the insulated cup 64 by. the metal ring 67. The intervening space between the front electrode 66 and rear electrode 65 is occupied by asuitable amount of granulated carbon resistance material. Fig. 9 clearly illustrates the general configuration of the microphone cell together with its supporting bracket. Sound waves projected through the mouthpiece 60 and upon the gold plated electrode 66 will compress and expand the carbon granulated material in the microphone cell and vary the resistance of the electrical circuit extending from the front electrode 66 to the rear electrode 65 in the ordinary operation of the transmitter.

While this telephone as described and constructed meets all the requirements of a practiced telephone for lntercommunicating use, it will be appreciated that, because of the low construction cost it finds a ready market as a toy. A telephone, to be put to such a use, must be ruggedly constructed due to the rough handling which ordinarily prevails when an instrument of this nature is used as a toy. The construction of the transmitter and receiver units, which are sealed in their casings, readily meets these requirements. In order that an instrument or this nature-may have a further appeal to juveniles, an arrangement simulating the calling device of an automatic telephone is provided. This comprises 'a disc 13 having a number of holes, as shown in Fig. 1, with suitable numerals visible therethrough. The disc 13 is arranged for rotation on a rivet '73 extending through the base member 5. n the .rear 'end of this rivet a ratchet arrangement 70' is attached, as shown in Fig. 10. The

ratchet 70 has a pair 01 pawls 71 and 72 cut on opposite sides thereof arranged so that by rotation of the dial 13 these pawls will rotate over the teeth 74 01' the ratchet wheel and generate a sound or noise similar to that made by an ordinary calling device.

Fig. 11 schematically illustrates the circuit connections existing between a pairof telephone instruments A and B each constructed accordin to the invention. A single pair of line conductors and 76 extend between the telephones A and. B. conductor 75 being tied to terminals 2l21', and conductor '76 being tied to termina s 22-22' of the respective substations. A small source of current which be supplied by dry cells C is provided and one post of the battery extends to terminal 20 while the opposite post extends to terminal 20'.

In the normal position the handsets 7 and '7 oi the substations A and B, respectively, are resting on their associated switch operating members 9 and 9' and maintain the sets of contact springs in the pwition illustrated in Fig. 3. With both telephones in this position when the user at the substation A' desires to call the person at substation E the handset 'i is removed from the cradle 6, thereby permitting the switch actuating member 9 to rise and allow contact springs 32 and 33 to close and springs 33 and 3a to open as shown in Fig. 4. A circuit is thereby completed from one pole of battery C, to terminal 20, contact springs 33 and 32 of substation A, in series with the receiver coil 11 and transmitter 10 of the handset line conductor 76, terminal post 22' of substation B, normally-closed contact springs 33 and 34., interrupter contacts 26', the winding of the buzzer 25', terminal post 20 and to the other post oi battery'C. The buzzer 25', terminal post 20 and to the other post of battery C. The buzzer 25' of substation B, however, does not operate in this circuit because oi the relatively high resistance of the receiver 11 and transmitter 10 of the headset '7 in substation A. To signal the person at substation B, the user of the telephone at substation A new presses down the switch ,operating arm!) into the position in which it is shown in Fig. 5. This action separates contact springs 32 and 33, brings together springs33 and 34 and likewise brings together contact springs 35 and 36. This last pair of springs close a shunt circuit around the receiver 11 and transmitter 10 of the handset 7 at substation A to remove the resistance of these elements from the signalling circult so that, this circuit is now completed'from one pole of battery C, terminal post. 20, through closed contact springs 36 and 35, terminal 22, conductor '76, closed contact springs 33' and 3d of substation B, interrupter contacts 26', the buzzer winding 25', terminal 20' to the other pole of battery C. The buzzer 25' rapidly opens and closes its circuit at the interrupter contacts 26' to signal the called subscriber. The user of the telestation A, as well as, contacts 32 and 33 are open,

phone at substation A after a short interval releases his finger irom the switch member 9, thereby permitting the contact springs of his telephone to assume the talking position shown in Fig. 4 and awaits the response of the person at substation B.

The user or the telephone at substation B in responding to the calling signal removes the handset 7 from the switch actuating member 9, thereby permitting contact springs 32 and 33 to close. Contacts 33' and 34 at the same time are opened and disconnect the buzzer 25 from the battery circuit. A talking circuit between the two telephones is now established over the following path; one pole oi battery C, terminal 20, closed contact springs 33 and 32, receiver 11 and transmitter 10 of the handset '7 in series, terminal 22, conductor '76, terminal 22', contact springs 33' and 32', transmitter 10 and receiver 11' in series in the handset 7', terminal 20' and then to the other pole of battery C. Current for talking and listening is furnished by the battery C. 'Upon the replacement of the handsets at substations A and B the circuits are again placed in their original condition.

The circuit connections of telephone B with the line wires is slightly different from telephone A and the operation of this substation will now be pointed out. Upon initiating a call the user of the telephone at substation B removes his hand- 105 set 7 from the switch operating member 9, thereby permitting contact springs 32' and 33' to close, and at the same time contact springs 33' and 34 to open. A circuit path is thereby prepared extending from one pole of the battery C, to terminal 20', receiver 11, transmitter 10' of the handset 7, contact springs 32 and 33', terminal post 22', conductor 76. However, due to the fact that at this time contact springs 35 and 36 of subno current flows over this circuit. In order to signal the party at the substation A the user of the telephone B presses down the switch operating member 9' with his finger, as shown in Fig. 5, and closes the contact springs 35' and 36'. Contacts 32' and 33' are also opened at this time and, therefore, no current flow takes place through the units of the handset 7'. The signailing circuit extends from one pole of battery B, terminal 20', interrupter contact 26, winding of the buzzer 25, contact springs 34 and 33, terminal 20 to the other pole of battery B. The buzzer 25 consequently operates to signal the user of the telephone at substation A. By listening in occasionally between intervals during his operation of the switch actuating member 9' the user at substation B ascertains when the person at substation A responds to the signalling by the removal of his handset '7 from the cradle of the telephone. When this occurs the circuit for the buzzer 25 is opened at contact springs 33 and 34 to stop the signalling if such signalling has not already been stopped, and at contacts 32 and 33, a circuit extending through the transmitter 10 and 1 receiver 11 of the handset '7 at substation A is completed over terminals 20 and 22, in series with the transmitter 11 and receiver 10' of the handset 7' at the substation B, and conversation now may proceed. The replacement of the respective handsets upon the substation cradle members restore the circuits to their normal condition.

It should be noted particularly in the above circuit operations that when telephone station A signals station B the signalling current for operating buzzer 25' takes a path extending over the leads extending from the battery C and the line conductor 25, wizdle when station E signals scstion A the bwzer 25 is secreted over a circuit path extending from cattery conductor and line wire 75. In all cases and listening place over a circuit from the batter; conduc'ror and over the line wire $6, to the exclusion of conductor i5. From this it 'is seen that the Kine wire 78 is used for both signalling and talking, while Zine wire '25 is used only for signalling. By arrangim the circuits in this mazmer the number of conductors extending between the telephones is reduced as well as effectmg a simplifiesion of the internal wiring of each telephone.

What is claimed is:

1. In a telephone set, a base having a cradle member thereon, a handset normally resting on said cradle, a set of circuit controlling springs within said base, a handset controlled switching member extending exterior to said era/die member controlling certain of said springs responsive to the removal of said handset from the cradle member for performing certain circuit switching operations, said switching member than manually operated to pezform a switching operation of said springs different than those performed by said handset.

2. In a telephone set of the cradle ime h ving a handset, a. switching member in said set engaged by said handset in its normal position, a plurality of sets of contact springs in said set con- .trolled by said switching member, one set of said contact springs closed by said switching member in its normal position with the handset on the set, another set of contact springs closed by the removal 01 said handsetfrom the switching mememme member to clcse one sex? of contact springs and open a second set, said member operated so open said sei'. of springs and close said second set consequent to the removal of the handsei; from the cradic and the reiease of said switching member, said switching member thereupon ocerative independent of any action of said handwfi to again close said first set of springs and open said second set and in addition close a third sci; of said springs.

4. In a cradle type telephone having a handset, a set of five contact springs, a switching member for actuating said springs, said member one end thereof protruding from the cradle set a predetermined maximum distance under the tension of the second spring of said set, the first spring thereof at the same t me engaging second spring, the slight movement of said member resulting from the placing of the handset on the cradle disengaging said first and second springs and bringing said second springs into engagement with a third spring, said member also directly operated manually to a position in the direction of but beyond that attained by the placing of the handset on the cradle, and means in said second spring actuating the fourth spring of said set into engagement with the fifth spring consequently only to the manual movement of said member.

HARRY H. IDE.

iso- 

